This invention generally relates to new and improved tunnel construction systems and components thereof, having particular adaptability for off-site component manufacturing and convenient on-site assembly of vehicular passageways to avoid physical barriers.
The construction of tunnels has generally focused on the tedious fabrication of reinforced structures within bored rock, earth and the like passageways. Typically in bored tunneling, the strength of the finished tunnel comes from the dense material through which the tunnel is bored and interior panels, decorative walls and the like add marginal strength to the structure, being primarily used for aesthetic and water control purposes. As a result, prior art tunneling systems have generally concerned themselves with problems associated with working in confined passageways, particularly the problems associated with limitations to size of machinery which can be utilized to fabricate and/or assemble a reinforced structure within the tunnel. Because of such concern there has typically been opposition to the use of large prefabricated sections with the attendant difficulties of handling and/or assembling such sections in the confines of a bored tunnel. Thus, the emphasis in the prior art relating to the use of prefabricated components for tunnel construction has been to the erection and assembly of a multiplicity of modest sized panels, that may be conveniently handled by a few workers, to fabricate a constructed tunnel. The assembling of multiple modest sized panels, however, has its disadvantages in that large numbers of joints must be sealed which significantly increases the risk of leak failure as well as the cost of construction labor in the project. In many applications, the cost of prefabricated panels, the cost of assembly and the increased cost and quantity of failure prone sealed joints cannot be justified so prefabrication is avoided and a typical concrete tunnel is poured, sprayed, troweled or otherwise formed in place.
It is an object of the instant invention to provide an improved system for assembling vehicular tunnels. It is also an object to provide an improved system comprising the use of prefabricated components. It is a further object to provide an improved system for fabricating tunnels comprising prefabricated components which require fewer seals during installation. It is a still further object of the invention to provide new prefabricated components for use in fabricating vehicular tunnels. These and other objects will become apparent from the following disclosure of the invention.